This invention relates to a disposable undergarment such as a disposable diaper, a diaper cover, a training pant or an incontinent pant.
Connectional disposable diapers of open-type are provided with tape fasteners transversely extending outward from transversely opposite side edges of a rear waist region and a target tape strip attached to outer surface of a front waist region. In an example of such diaper, hook and loop members of the mechanical fastener known by the trade name such as MAGIC TAPE or VELCRO are used as the tape fastener and the target tape strip, respectively. Specifically, the hook member is attached to the inner surface of each base tape strip and a rectangular strip of the loop member is attached to the outer surface of the front waist region at a desired position to form a landing zone. The tape fasteners are detachably anchored on the target tape strip to connect the front and rear waist regions of the diaper to each other.
Such diaper is disclosed, for example, in Japanese Patent Application Publication Nos. 1997-38139A, 1997-191908A, 1998-309299A and 1998-328237A. The diaper disclosed in these Publications uses a non-stretchable loop member as the target tape strip.
With the diaper having an elastic stretchability, it is assumed that the non-stretchable loop member serving as the target tape strip is attached to the front waist region which is substantially in its non-stretched condition. In this case, the target tape strip will restrict a stretchability of the front waist region in its zone provided with the target tape strip. Consequently, the diaper will be derived of its stretchability in the zone thereof provided with the target tape strip.
It is an object of this invention to provide a disposable undergarment having an elastic stretchability so that, if a non-stretchable target tape strip is attached to the outer surface of the substantially non-stretched front waist region, the front waist region may be kept stretchable even in the attachment zone of the target tape strip.
According to this invention, there is provided a disposable undergarment comprising a basic structure contoured by transversely opposite side edge portions longitudinally extending in parallel to each other and longitudinally opposite edge portions transversely extending in parallel to each other and having a front waist region to cover a wearer""s belly, a rear waist region to cover the wearer s back and a crotch region extending between the waist regions, a pair of tape fasteners attached to transversely opposite side edge portions of the rear waist region and a non-stretchable target tape strip attached to outer surface of the front waist region so that the tape fasteners serve as male members adapted to be separably anchored on the target tape strip serving as a female member and thereby to connect the front and rear waist regions to each other.
According to this invention, of the front waist region, the rear waist regions and the crotch region, at least the front waist region is elastically stretchable at least transversely of the undergarment; the target tape strip comprises a flexible film layer having transversely opposite side edges extending longitudinally and upper and lower edges extending transversely of the undergarment and a plurality of long fibers extending longitudinally in parallel one to another on an outer surface of the film layer between upper and lower edges; the film layer is formed with a plurality of slits arranged to be transversely spaced one from another by a predetermined dimension and to extend longitudinally between a vicinity of the upper edge and a vicinity of the lower edge; the target tape strip is attached to the front waist region being substantially in non-stretched state; and the long fibers are bonded to the film layer in the vicinity of the upper and lower sides the film layer.
The expression xe2x80x9csubstantially in non-stretched statexe2x80x9d used herein should be understood to include both the state in which the front waist region is not stretched at all and the state in which the front waist region is slightly stretched.
According to one embodiment of this invention, the long fibers are slackened outward from the outer surface of the film layer between the upper and lower edges of the film layer.
According to another embodiment of this invention, the film layer is formed with a plurality of perforated lines arranged to be transversely spaced one from another by a predetermined dimension and to extend between the vicinity of the upper edge and the vicinity of the lower edge so that the film layer is easily torn apart along the perforated lines to for the film layer with the slits.
According to still another embodiment of this invention, the film layer is bonded to the front waist region by means of plural stripes of adhesive arranged to be transversely spaced one from another and to extending longitudinally of the undergarment.
According to further another embodiment of this invention, the undergarment comprises a liquid-pervious topsheet to contact the wearer""s skin, a liquid-impervious backsheet not to contact the wearer""s skin and a liquid-absorbent core disposed therebetween.